The spin cycle of a washing machine removes water centrifugally from wet clothes by spinning the clothes at high speed in a spin basket. In order to reduce the possibility of injury to the user during the spin cycle, it is known to use an electronically actuated lock for holding the washing machine lid in the closed position. U.S. Pat. Nos. 6,363,755; 5,823,017; and 5,520,424, assigned to the present assignee and hereby incorporated by reference, describe several locking mechanisms.
In order to prevent tampering with the lock mechanism, for example, by holding the lid open when the lock is actuated, it is known to provide for lid closure sensing to ensure that the lid is in a proper position before the lock mechanism is engaged. Conventional mechanical lid closure switches can often be defeated by wedging the switch open, for example, with the end of a pencil or the like. U.S. Pat. No. 7,251,961, assigned to the assignee of the present invention and hereby incorporated by reference, describes a lid sensor using a magnet and electrical reed switch to detect lid closure. The use of a magnetic actuator reduces the possibility of casual tampering.
US patent application 2012/0312594, assigned to the assignee of the present invention and hereby incorporated by reference, describes a lock mechanism in which the magnet is incorporated into a hook or striker that engages the latch. The magnet activates an anti-tamper feature which indicates that the striker and not a foreign object is engaging the latch. In this design, the striker is spring mounted to follow a serpentine path as it engages the latch. This path further defeats simple tampering by requiring that the striker and engagement of the latch have a particular dimension and are able to navigate flexibly along that path. A similar design that does not require the magnet feature is disclosed in U.S. provisional patent application 61/911,659 also incorporated by reference. Each of the above listed patents and applications is hereby incorporated by reference.